Polymeric base propellant compositions containing lithium fluoride catalyst



United States Patent 3,156,594 PULYMERKZ BASE PROPELLANT COB/WOSITIUNSCONTING LIT FLUURIDE CATALYST Marvin Duane Horton, Provo, Utah, assignorto the United States of America as represented by the Secretary of theNavy No Drawing. Filed June 10, 1964, Ser. N 374,214 4 Claims. (Cl.149-19) (Granted under Title 35, US. Code (1952), sec. 266) Theinvention herein described may be manufactured and used by or for theGovernment of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

This invention relates to a new solid propellant composition, and moreparticularly to a solid propellant composition with a plateau typeburning characteristic.

The velocity at which a solid propellant is consumed during operation iscalled the burning rate. It is measured in a direction normal to thepropellant surface and is usually expressed in inches per second. Mostof the new propellant compositions which have been developed Withinrecent years do not possess burning-rate characteristics comparable tothose of the old-fashioned compositions; that is, the logarithmic plotof burning-rate versus pressure no longer assumes a straight line calledlinear burning; but instead mesa and plateau burning have appeared. Aplateau-burning propellant is one for which the logarithmic plot ofburning-rate versus pressure deviates from that of linear in thefollowing manner. At low pressures, the burning-rate-pressurerelationship is generally linear with a moderately high pressureexponent. This is followed by a pressure range where the burning ratebecomes nearly constant. Finally, the burning rate becomes about assensitive to changes in pressure as it was at the low pressure.Significant advances have been made in improving solid propellantburning-rate characteristics by modification of the composition. Thegeneral purpose of the present invention is to blend lithium fluoridewith an inorganic oxidizer, a polymeric fuel binder and a low molecularresin such as one of the condensation polymers of epichlorohydrin andbisphenol-A (sold under the tradename Epon 828) to form a rocketpropellant composition exhibiting the plateau burning phenomenon.

It is therefore an object of this invention to provide a new propellantcomposition having a controlled burning rate.

Another object of this invention is to provide a propellant compositionhaving improved physical properties.

Yet another object is to provide a propellant which will find use inrocket motors of simplified design.

Other objects, features and many of the attendant advantages of thisinvention will become easily appre- 3,156,594 Patented Nov. 10, 1964ciated as the same become better understood by reference to thefollowing description.

The example given herein is a typical formulation Whereinlithiumfluoride apparently influences the burning rate.

Ingredients: Percent by weight Ammonium perchlorate Polybutyl acrylicacid terpolymer 20.4 Epichlorohydrin and bisphenol resin 3.6 Lithiumfluoride (powder) 1 The oxidizer used above was made up of ammoniumperchlorate of the following three particle sizes:

10 weight percent about 65;]. 50 weight percent about 93 weight percentabout g The above ingredients were blended in a mixer until homogenietyresulted. The mixture was then cast into the desired configurations andcured for several days at about 130 F.

It is possible that the coarse ammonium perchlorate and a little lithiumfluoride will change many composite propellant compositions toplateau-burning types.

Obviously many modifications and variations are possible in the light ofthe above teachings. It is therefore to be understood that within thescope of the appended claims the invention may be practiced otherwisethan as specifically described.

What is claimed is:

l. A propellant composition consisting essentially of the followingingredients:

Ammonium perchlorate Lithium fluoride Polybutyl acrylic acid terpolymerA resin consisting of a condensation product of epichlorohydrin andbisphenol A.

2. The composition of claim 1 wherein the ammonium perchlorate comprisesa mixture of particle sizes of about 10 weight percent of 65 50 weightpercent of 93 ,u. and about 90 weight percent of 130;.

3. A propellant composition consisting essentially of the following:

Ingredients: Percent by weight Ammonium perchlorate 75 Lithium fluoride1 Polybutyl acrylic acid terpolymer 20.4 Resin consisting ofepichlorohydrin and hisphenol 3.6

4. The composition of claim 3 wherein the ammonium perchlorate consistsof particle sizes ranging from 63 1. to 1301i.

No references cited.

1. A PROPELLANT COMPOSITION CONSISTING ESSENTIALLY OF THE FOLLOWINGINGREDIENTS: AMMONIUM PERCHLORATE LITHIUM FLUORIDE POLYBUTYL ACRYLICACID TERPOLYMER A RESIN CONSISTING OF A CONDENSATION PRODUCT OFEPICHLOROHYDRIN AND BISPHENOL A.